Method of testing magnetizable objects



0a 9,1928. U I 1,686,815

E S. [MES- METHOD OF TESTING IAG NETIZAB LE OBJECTS I Filed Kay 25, 1925 a Sheets-Sheet 1 I V INVENTOH- Elmer S-Imes Oct. 9, 1928. 1,686,815

E. S. IMES METHOD OF TESTING IAGNETIZABLE OBJECTS Filed May 26, 1925 3 Sheets-Sheet 2 IN l/EN TOR .E 211167 8. Imes ri/Mr Oct. 9, 1928. 1,686,815

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METHOD OF TESTING HAGNETIZABLE OBJECTS Filed llay 26, 1925 a Sheets-Sheet 3 INVENTUR Ilrner 8- 171188 Arrbhn/n i plication was filed i atented gettin 192%.

ELMER s. mes, or JERSEY CITY,

PATENT OFF-WE.

NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS,

T0 MAGNETIC ANALYSIS CORPORATION, OF LONG ISLAN CITY, NEW YORK, A COR- PORATION OF NEW YORK.

METHOD! OF TESTING M.B GNETIZABLE OBJECTS.

Application filed m 26,1925 Serial m. 32,947.

My invention relates to methods of testing magnet-izable objects and is an improvement on the method and apparatus invented jointly by C. W. Burrows andv myself for which ap- October 20, 1923, Serial N 0. 669,726. It is a primary object of my present invention to provide a method for magnetically determining a plurality of physical characteristics of a specimen when all of such characteristics are unknown. More specifically, my invention relates to a method for determining the physical characteristics produced by the temperatures at which specimens of steel are quenched and drawn when neither the draw nor the quench temperatures are known. 7

It will be understood that the quench temperature controls grain size of a specimen an the draw temperature the structureor hai dness of the steel. In commercial practice it is impossible to hold either" the quenching temperature or the drawing temperature within close limits with the result that com mercial steel is apt to vary .widely from desired standard. Ordinary physical tests such as the Brinell, the tinguish between the factors of quench and draw. A specimen may be quenched at the desired temperature and either over orunderdrawn or it may be drawn at the desired temperature or either over or, under-quenched.

Again the specimen may vary from the standard in both of these factors. In other Words, it maybe either over-quenched and underdrawn, or over-quenched and over-drawn, or again it maybe under-quenched and overdrawn, or under-quenched'and underdrawn. For certain classes ofwork variations due to quench'are not of as great importance as variin other classes 01' ations due to draw and It is obviously work the reverse holds true.

of importance then to determine how the material under test varies from standard either as regards quench or as regards draw or as regards both quench and draw so as to discard the material which exceeds the tolerances set for either the quench or draw factors.

The ordinary physical tests, such as those -above mentioned, give a local measurement,

Rockwell, etc. do not d1staneously,

and itis desirable in practice to'provide for a continuous indication of the condition of the entire specimen as regards physical characteristics due to. quench and draw, so that any points in the specimen 'which varied from pre-determined standards could be detected.

object of my invention is to provide an improved. method of comparing any specimen with a standard of known quench to de termlne whether the specimen has been over or under quenched with respect to the standard,- to set positive and negative-tolerances, and to determine whether the specimen exceeds such tolerances.

Another object of my invention is to pro- Y vide a method which will not only ermit of testing for quench as above describe but will also permit of determininggwhether a specimen has lieen over or under drawn with respect to a standard, to establish positive and negative draw tolerances, and to determine whether the specimen falls within such tolerances.

A further object of myginvention is to provide for comparmg-a specimen of unknown quench and unknown draw witha standard of known quench anddfaw, to determine variations of the specimen from the standard as regards the factors of quench'and draw simulto measure the extentot the variation, and to determine whether the specimen falls within allowable limits as to either of such factors. i

A still further object of my invention is to provide for a continuous throughout its length to. determine its variance from standard as to quench or draw separately or simultaneously.

Other objects of my invention will appear as the specification of my invention proceeds.

In the accompanying drawings:

test of a specimen -,90 Figure 1 is adiagrammaticview of one form of my testing apparatus in which a specimen maybe testedas to one characteristic at a time E Figure 2 is a diagrammatic view of a modified form of testing apparatus in which thespecimen may be tested as to two charactens ties atthe same time;

I shown in Fig.2 v d 3 a modification Fig. 4 is a-further modification of the apparatus shown in Fig. 2.

' Referring to Figure 1, I have used the reference numeral 10 to indicate a primary circuit connected withv asource of alternating current which is not shown. In the circuit 10 there are two primary coils 11 and 12 respectively which are connected in series. In the m'a netic field of these coils and: preferably wit in these coils are two secondary coils13 and 14 respectively, which form part of a secondary or induced circuit 15. A dynamometer'is indicated as a whole at 16 which comprises the usual core 17 about which arewound the field coils 18, the latter being connected in series with the primary coils 11 and 12 in the primary circuit 10. The potential coil 19 of the dynamometer is connected in series with the secondary coils 13 and 14. The coils 13 and .14, however, are oppositely wound or connected in bucked relation so that thepotential coil 19receives only the difinduced in coils 13 and 14 respectively; he coils 11 and 12 are care- 7 fer'ential ener ful y balanced to produce magnetic fields of the same intensity and the coils 13 and 14 are carefully balanced so as normally to produce no current in the secondary circuit 15. The potential coil is provided with an indiqator needle 20 and dial 21.-

- current passing throng In order to vary the phase relation between coils 18 and coil 19.,- a] variable phase shifter 22 is connected across the primaryqcireuit,

' coils and -the?"dynamometer. vA non-in uctive resistance 23 is between the prima .The phaseshifter 22 is operated by a lever 26 to shift the a phase of current passing through the field coils 1-8. A pointer 27 serves to indicate the extent of phase variamen the dial of the phase shifter. '"Anindicator 28 is adjustable on the dial to register a certainpo'sitionpf the pointer 27 and a second indicator 29 is also adjustable on the dial of thephase shifter to indicate another.

- v approxlmately 9.0 degrees untll needle 20'- comes to zero position and indicator 29 is adposition of the pointer 27. 1

- The inter 20 of the, dynamometer is adapte to'make. contact with either contact 30 or contact 31 of two rela. circuits. When a the contact is closed throng contact pointer" 30, current from-battery 32 energizes lamp 33., When the pointer 22 contacts with contact pointer'3l, current from battery 32 energizes lamp 34. r

- My method of operationis based on the of the apparatus coils of discovery that witha certain magnetizing force in the -primarycircuit and a certain phase angle between the'field and potential e dynamometer, a maximum dif: ference will be shown on the dynamometer between two specimens of like quench but different draw and if the phase be shifted through an angle of approximatelyr90 no variations will be shown between the two is cimens but a maximum variation will be -s own between specimens of like draw, but

diflferentquench. r

In operation therefore, the apparatus must standard quenched temperature Q and drawtemperature D ,hree standards are prepared which are of the same composition as the specimens to be tested.v For convenience,

these standards will be referred to as A, B and C, the standard A is quenched at temperature Q and drawn at temperature D. Standard B be set either to determine variations in quench or in draw. Having determined a certain is also uenched at temperature Q, but drawn at a di erent temperature D; StandardG is uenched at a different uenclr temperature-Y f but drawn at the stan ard draw tempera.- ture D. Standard A is now Placed in the secondary coil 13 and Bin the secondary coil 14 and t shifter 22 are adjusted until the widestvariation is shown in the dynamometer '16. Be-

cause the twospecimens are quenched atthe' same temperature this must represent the variationproduced'by' .the difference of draw e variable resistance 23', and phase betweenqqgstandards a and B; The. phase shifte is. now adjusted until the needle: 20,

comes to-a neutral or zero position indicating no difference betweenthe two standards. The

alinement withv the pointer. 27 to mark-the position to which the phase shifter must be adjusted to set the apparatus for measuring variations of quench, for in-this position it is evident that the apparatus is, insensitive to variations of draw between the two standards. The standard B is now withdrawn from coil 14 and standard C is inserted. This standard, it will be recalled, is drawn at the same temperature as standard A but is justed to alinement withipointer 27. to indicate the shift of phase necessary to eliminate variations of quench and determine variations of draw, Theapparatus is now ready to test specimens whose quenchtemperature and draw temperature are not-known.

The

indicator 28 is then'shifted 'on" the-dial ,to

Standard'C is withdrawn from coil 14 and a specimen to be tested is inserted in its place.

ment may be adjusted by means of the variat a higher or lower temperature,'the needle? will move to the right or the left as the case may be, and the variation ma be read on the dial 21. Then the phase shi ter is adjusted until the needle points to indicator 29 when the readingof needle 20 with respect to the dial 21, will indicate whether the specimen was drawn at the standard temperature D or whetherit is drawn at above or below that standard. The sensitivity of the instruable resistance Contacts and 31 are also adjustable in accordance with the tolerance allowable. When a specimen exceeds the tolerance in one direction or the other, lamps 33 or 34c will be lighted. Lamp 33-for instance, may indicate that the specimen is coarser than the standard by such an amount as to render it unsuitable for the particular work for which it is intended, while 34 will indicate that it is finer than the permissible grain size-"The apparatus may be adjusted fed through the or a given tolerance of quench or of draw by moving contact points 30 and 31 withv res ct to the zero position of needle 20 or by ad usting variable resistance 25 to-adjust the sensitivity of the apparatus.

If the specimen to be tested is in the; form of a .wire, rod or strip of metal, it may be secondary coil 14 at any suitable rate of speed and the needle 20 will indicate the degree of departure of the specimen from the standard. with respect to either uench or draw depending upon the setting of the phase shifter 22, and wherever the variation exceeds the established tolerance either on the plus or minus side, the same will belindicated by the lighting of lamps 33 or 34. It will be evident of course, that any other form of signal can be iisedto indicate any variation of the specimen beyond the.

tolerances set, The relay circuits may control a marking devicewhich will mark the specimenwherever the variations exceed the tolerances set so that after the specimen has run through .the' testing apparatus it will bepossible to locate andcut out the faulty sections.

With the apparatus as shown in Figure 1,

the specimen must be run through the test coil 14' at one setting of the phase shifter to determine variation due to' quench and another setting of the phase shifter to determine variation due to draw. The modification shown in. Fig. 2 permits of taking readings" of draw and quench simultaneously at a single run ofthe specimen through the apparatus. In this figure parts which coi-respend to those shown in Fig.- 1 are indicated justed by operating with like or corresponding numerals. The

19 of dynamometer 16. Test coils 13 and 14: are connected in bucked rclationin a secondary circuit 15 which includes the potential coil 19 of dynainometer 16 A phase shifter 22 serves to shift the phase of current passing through field coils 18 of dynainometr 16 and a phase shifter 22" serves to shift the phase of coils 18 of dynalnometer 16*. P0 ntial coil 19* carries an indicator needle 20 which swings over the dial 21 and potential coil 19 carries a needle 20 whichswings over the dial 21". Obviously relay signal circuits could be controlled by each dynamometer, after the manner shown in Fig.v 1, but for the sake of clearness they have been omitted from the drawing.

In setting this apparatus for test, a procedure is followed similar to that described above in connection with the apparatus shown in Fig. 1. Standard A is placed in the test coils 13 and 13 and standard B in the test coils 14: and 1 1". The apparatus is then ad: variable resistance 28 and phase shifter 22 to show the maximum variation in the dynamometer 16, after which phase shifter 22 is adjusted to bring the needle 20 to neutral position. the settlng for quench. Standard B is then replaced with standard C and phase shifter '22 is adjusted to bring the needle 20 to neu-- This gives tral position, which gives the setting .for

reading of dr aw. Standard C is then removed and specimens to be tested are passed through the test coils 14 and 14 whereupon dynamometer 16 will indicate variations from the standard of quench and dynamometer 16 .variationsfrom the standard of draw. The

test coils of circuit 15 and 15 are not 10- cated in the, same position with respect to the primary coils 11 and 12. The test coils of circuit 15 being 'nearer the center of the primary coils will be subjected to a more intense-magneticv field than the other. test coils which are close to the ends of theprimary "coils. fConsequently, there will be a varia tion in the sensitivity of the two dynamometers.- I have found that better results are obtained by using a somewhat different field intensity ,for testing for quench. Consecoils are adjustable within the primary so induced by the primary coils, while the pair quently, the positions of the pairsof test sessing two show no variation between sessing two physical characteristics of nn.-

known value, which consists in subjecting two standards to a varying magnetic field, said characteristics being pre-determined in each of said standards, the standards being alike as to the value of one of said characteristics but differing as to the value of the other of said physical characteristics, noting on a dynamometer the difi'erential energy absorbed by the two standards, adjusting the phase variance between the coils of the dynamometer to indicate no Variation between the standards, replacing the second standard with the object to be tested, and noting the difierential energy indicated by the dynamometer.

I 3. A-method of determining one physical characteristic of a magnetizable object posphysical characteristics of unknown value, which consists in subjecting to a magnetic field two standards possessing said physical characteristics, said characteristics being pre-determined, the two standards being alike as to the value of one of said characteristics but diiiering as to the value of the other of said characteristics, measuring on a dynamometer the difierential energy absorbed by the two standards, adjusting the phase variance between the coils of the dynamometer and varying the maximum in.- tensity of said magnetic field to show a maximum reading onthe dynamometer, adjusting the phase variance to show a zero indication on the dynamometer, the standards with theobject to be tested, and noting the difiere'ntial energy indicated by the dynamometer. 4

4. A method of determining one physical chdracter-istic of a magnetizable object possessing two physical characteristics of unknown value, which consists placingtwo standards in the secondary coils of two trans formers, both of the standards being! as to one of said characteristics and di ering as to the other of said characteristics, the two secondary coils being bucked and connected in serieswith the potentialcoil of a dynas mometer, the primary coils of iihe transiform-v (am being connected in series with the field coil of said dynamometer, energizing the transformers, noting the differential energy indication ,o the dyna'mometer, varying the" phase relation between the field and potential coils of .thedynamometer'to show .a zero indication, replacing.

and indicating by means of the dynamometer replacing one of alike.

one'of thestandards. with the object to be tested,

- the-variation standards in the secondary coils of two transformers both of the standards being alike as to one of said characteristics and .diflering as to the other of said characteristics, the two secondary coils being bucked and connected in series with the potential coil of a dyna mometer, the primary coils being connected in series with the field coils of said dyna -mometer, energizing the transformers, varying the maximum field intensity of the transformers and adjusting the phase relation between the field and potential coils of the dynamometer to indicate the maximum variation between the two standards, adjusting sa d phase relation to show no variation between the standards, replacing one of the standards with the object to be tested, and indicating by means of the dynamometer the variation of the bbject from the remaining to s ow a zero readmg, replacing the second standard with a lee third standard differing from the first stand- -ard as to value of the other of said physical characteristics, observing on a second dynamometer the difierential energy absorbed by the first and third standards, adjusting the ond dynamometer to show a zero reading,.replacing the thirdstandard with the object to be tested, and noting variations of the s men from the first standard as to one p ysical characteristic on one dynamometer and as to the other physical haracteristic on the aother dynamom'eter,

7. A method of testing. a magnetizable object to determine simultaneously two physical characteristics of unknown value, which con sists in subjecting to a varying magnetic field two standards in which the values ofsa-id hysical characteristics have been pre-determined, the first standard differing from the second standard as to the value of one of said physicalcharacteristics, observing on a dynamometer the difierential energy absorbed by the two standards, varying the maximunt'intensity of said field and adjust ing the dphase variance between the coils of the 'ynamometer to show a phase r la'tion between the 'coilsof the sec- 7 first standard as to value of the other of said physical eharacteristics, observing on a. sec-- ond dynamometer the differential energy ab sorbed by the first and third standards, adjusting-the phase relation between the coils 90f the second dynamemeter to show a zero .10 the ohject to betested, and neting variations of the-specimenirom the first 'standard as reading replacing the'thir d' standard with mometer and as-Zte' the other physical charac 

